1. Field of the Invention
The present disclosure relates to signal sampling techniques, and more particularly, to methods for adjusting a sampling clock of a sampling circuit and related apparatuses.
2. Description of the Prior Art
For a sampling circuit, such as an analog-to-digital converter (ADC), the phase selection mechanism of the sampling clock has a significant influence to the quality of sampled data. For example, in a liquid crystal display (LCD) device, an ADC is typically employed to sample an analog image signal according to a sampling clock to generate required digital image data. If the phase of the sampling clock of the ADC is selected improperly, the image quality of the output signal is easily degraded. Therefore, an auto phase setting technique is usually applied in LCD devices to adjust the phase of the sampling clock of the ADC.
The conventional approach for deciding the phase of the sampling clock of the ADC is to calculate the sum of absolute difference (SAD) of sampled data output from the ADC with respect to different candidate sampling phases. Then, multiple SADs corresponding to different candidate sampling phases are compared to identify a sampling phase corresponding to the maximum SAD as the best sampling phase for the ADC. However, this approach is not considered accurate. For example, the sampling phase selected is usually far from ideal if the image in nature is composed of numerous stripes, thereby resulting in a degradation of image quality.